Can't access WordPress dashboard

I'm building our wp site and recently updated my themes and plugins. Now, when I attempt to login to my wp dashboard I've received different errors. The first error was related to my Astrid Pro plug-in update. Astrid Pro support suggested I manually upload the plugin via FTP, which I tried but it didn't fix the problem:
Fatal error: Call to undefined function register_setting() in /home/content/t/i/m/times2studio/html/wp/wp-content/plugins/astrid-pro/updates.php on line 58

Now, I'm getting this error which makes me think something of a bigger problem is going on:
Fatal error: Call to undefined function register_setting() in /home/content/t/i/m/times2studio/html/wp/wp-content/plugins/simple-custom-css/includes/admin.php on line 85

I've tried searching online for help but no fixes have helped. I've tried temporarily changing the names of both my plug-ins and themes folders. Up until a few minutes ago, my site was actually previewing correctly (I just couldn't edit anything) but now it has reverted back to a base theme so I'm really stuck.

I wasn't able to add your plugin to my dashboard since I can't access my WP dashboard, so I'm not sure what to do.

Thank you for your help!